229 lines
7.9 KiB
Go
229 lines
7.9 KiB
Go
/*
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* Copyright © 2018 A Bunch Tell LLC.
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*
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* This file is part of WriteFreely.
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*
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* WriteFreely is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License, included
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* in the LICENSE file in this source code package.
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*/
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package writefreely
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import (
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"fmt"
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"github.com/microcosm-cc/bluemonday"
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stripmd "github.com/writeas/go-strip-markdown"
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"github.com/writeas/saturday"
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"github.com/writeas/web-core/stringmanip"
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"github.com/writeas/writefreely/parse"
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"html"
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"html/template"
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"regexp"
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"strings"
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"unicode"
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"unicode/utf8"
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)
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var (
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blockReg = regexp.MustCompile("<(ul|ol|blockquote)>\n")
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endBlockReg = regexp.MustCompile("</([a-z]+)>\n</(ul|ol|blockquote)>")
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youtubeReg = regexp.MustCompile("(https?://www.youtube.com/embed/[a-zA-Z0-9\\-_]+)(\\?[^\t\n\f\r \"']+)?")
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titleElementReg = regexp.MustCompile("</?h[1-6]>")
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hashtagReg = regexp.MustCompile(`{{\[\[\|\|([^|]+)\|\|\]\]}}`)
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markeddownReg = regexp.MustCompile("<p>(.+)</p>")
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)
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func (p *Post) formatContent(c *Collection, isOwner bool) {
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baseURL := c.CanonicalURL()
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if !isSingleUser {
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baseURL = "/" + c.Alias + "/"
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}
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p.HTMLTitle = template.HTML(applyBasicMarkdown([]byte(p.Title.String)))
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p.HTMLContent = template.HTML(applyMarkdown([]byte(p.Content), baseURL))
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if exc := strings.Index(string(p.Content), "<!--more-->"); exc > -1 {
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p.HTMLExcerpt = template.HTML(applyMarkdown([]byte(p.Content[:exc]), baseURL))
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}
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}
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func (p *PublicPost) formatContent(isOwner bool) {
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p.Post.formatContent(&p.Collection.Collection, isOwner)
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}
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func applyMarkdown(data []byte, baseURL string) string {
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return applyMarkdownSpecial(data, false, baseURL)
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}
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func applyMarkdownSpecial(data []byte, skipNoFollow bool, baseURL string) string {
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mdExtensions := 0 |
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blackfriday.EXTENSION_TABLES |
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blackfriday.EXTENSION_FENCED_CODE |
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blackfriday.EXTENSION_AUTOLINK |
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blackfriday.EXTENSION_STRIKETHROUGH |
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blackfriday.EXTENSION_SPACE_HEADERS |
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blackfriday.EXTENSION_AUTO_HEADER_IDS
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htmlFlags := 0 |
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blackfriday.HTML_USE_SMARTYPANTS |
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blackfriday.HTML_SMARTYPANTS_DASHES
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if baseURL != "" {
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htmlFlags |= blackfriday.HTML_HASHTAGS
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}
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// Generate Markdown
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md := blackfriday.Markdown([]byte(data), blackfriday.HtmlRenderer(htmlFlags, "", ""), mdExtensions)
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if baseURL != "" {
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// Replace special text generated by Markdown parser
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md = []byte(hashtagReg.ReplaceAll(md, []byte("<a href=\""+baseURL+"tag:$1\" class=\"hashtag\"><span>#</span><span class=\"p-category\">$1</span></a>")))
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}
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// Strip out bad HTML
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policy := getSanitizationPolicy()
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policy.RequireNoFollowOnLinks(!skipNoFollow)
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outHTML := string(policy.SanitizeBytes(md))
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// Strip newlines on certain block elements that render with them
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outHTML = blockReg.ReplaceAllString(outHTML, "<$1>")
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outHTML = endBlockReg.ReplaceAllString(outHTML, "</$1></$2>")
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// Remove all query parameters on YouTube embed links
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// TODO: make this more specific. Taking the nuclear approach here to strip ?autoplay=1
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outHTML = youtubeReg.ReplaceAllString(outHTML, "$1")
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return outHTML
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}
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func applyBasicMarkdown(data []byte) string {
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mdExtensions := 0 |
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blackfriday.EXTENSION_STRIKETHROUGH |
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blackfriday.EXTENSION_SPACE_HEADERS |
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blackfriday.EXTENSION_HEADER_IDS
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htmlFlags := 0 |
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blackfriday.HTML_SKIP_HTML |
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blackfriday.HTML_USE_SMARTYPANTS |
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blackfriday.HTML_SMARTYPANTS_DASHES
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// Generate Markdown
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md := blackfriday.Markdown([]byte(data), blackfriday.HtmlRenderer(htmlFlags, "", ""), mdExtensions)
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// Strip out bad HTML
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policy := bluemonday.UGCPolicy()
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policy.AllowAttrs("class", "id").Globally()
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outHTML := string(policy.SanitizeBytes(md))
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outHTML = markeddownReg.ReplaceAllString(outHTML, "$1")
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outHTML = strings.TrimRightFunc(outHTML, unicode.IsSpace)
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return outHTML
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}
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func postTitle(content, friendlyId string) string {
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const maxTitleLen = 80
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// Strip HTML tags with bluemonday's StrictPolicy, then unescape the HTML
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// entities added in by sanitizing the content.
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content = html.UnescapeString(bluemonday.StrictPolicy().Sanitize(content))
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content = strings.TrimLeftFunc(stripmd.Strip(content), unicode.IsSpace)
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eol := strings.IndexRune(content, '\n')
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blankLine := strings.Index(content, "\n\n")
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if blankLine != -1 && blankLine <= eol && blankLine <= assumedTitleLen {
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return strings.TrimSpace(content[:blankLine])
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} else if utf8.RuneCountInString(content) <= maxTitleLen {
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return content
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}
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return friendlyId
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}
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// TODO: fix duplicated code from postTitle. postTitle is a widely used func we
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// don't have time to investigate right now.
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func friendlyPostTitle(content, friendlyId string) string {
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const maxTitleLen = 80
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// Strip HTML tags with bluemonday's StrictPolicy, then unescape the HTML
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// entities added in by sanitizing the content.
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content = html.UnescapeString(bluemonday.StrictPolicy().Sanitize(content))
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content = strings.TrimLeftFunc(stripmd.Strip(content), unicode.IsSpace)
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eol := strings.IndexRune(content, '\n')
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blankLine := strings.Index(content, "\n\n")
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if blankLine != -1 && blankLine <= eol && blankLine <= assumedTitleLen {
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return strings.TrimSpace(content[:blankLine])
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} else if eol == -1 && utf8.RuneCountInString(content) <= maxTitleLen {
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return content
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}
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title, truncd := parse.TruncToWord(parse.PostLede(content, true), maxTitleLen)
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if truncd {
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title += "..."
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}
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return title
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}
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func getSanitizationPolicy() *bluemonday.Policy {
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policy := bluemonday.UGCPolicy()
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policy.AllowAttrs("src", "style").OnElements("iframe", "video", "audio")
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policy.AllowAttrs("src", "type").OnElements("source")
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policy.AllowAttrs("frameborder", "width", "height").Matching(bluemonday.Integer).OnElements("iframe")
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policy.AllowAttrs("allowfullscreen").OnElements("iframe")
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policy.AllowAttrs("controls", "loop", "muted", "autoplay").OnElements("video")
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policy.AllowAttrs("controls", "loop", "muted", "autoplay", "preload").OnElements("audio")
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policy.AllowAttrs("target").OnElements("a")
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policy.AllowAttrs("style", "class", "id").Globally()
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policy.AllowURLSchemes("http", "https", "mailto", "xmpp")
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return policy
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}
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func sanitizePost(content string) string {
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return strings.Replace(content, "<", "<", -1)
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}
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// postDescription generates a description based on the given post content,
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// title, and post ID. This doesn't consider a V2 post field, `title` when
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// choosing what to generate. In case a post has a title, this function will
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// fail, and logic should instead be implemented to skip this when there's no
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// title, like so:
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// var desc string
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// if title == "" {
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// desc = postDescription(content, title, friendlyId)
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// } else {
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// desc = shortPostDescription(content)
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// }
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func postDescription(content, title, friendlyId string) string {
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maxLen := 140
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if content == "" {
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content = "WriteFreely is a painless, simple, federated blogging platform."
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} else {
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fmtStr := "%s"
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truncation := 0
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if utf8.RuneCountInString(content) > maxLen {
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// Post is longer than the max description, so let's show a better description
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fmtStr = "%s..."
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truncation = 3
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}
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if title == friendlyId {
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// No specific title was found; simply truncate the post, starting at the beginning
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content = fmt.Sprintf(fmtStr, strings.Replace(stringmanip.Substring(content, 0, maxLen-truncation), "\n", " ", -1))
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} else {
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// There was a title, so return a real description
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blankLine := strings.Index(content, "\n\n")
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if blankLine < 0 {
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blankLine = 0
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}
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truncd := stringmanip.Substring(content, blankLine, blankLine+maxLen-truncation)
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contentNoNL := strings.Replace(truncd, "\n", " ", -1)
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content = strings.TrimSpace(fmt.Sprintf(fmtStr, contentNoNL))
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}
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}
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return content
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}
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func shortPostDescription(content string) string {
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maxLen := 140
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fmtStr := "%s"
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truncation := 0
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if utf8.RuneCountInString(content) > maxLen {
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// Post is longer than the max description, so let's show a better description
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fmtStr = "%s..."
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truncation = 3
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}
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return strings.TrimSpace(fmt.Sprintf(fmtStr, strings.Replace(stringmanip.Substring(content, 0, maxLen-truncation), "\n", " ", -1)))
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}
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